21271218 has 8 divisors (see below), whose sum is σ = 42542448. Its totient is φ = 7090404.

The previous prime is 21271207. The next prime is 21271223. The reversal of 21271218 is 81217212.

It is a sphenic number, since it is the product of 3 distinct primes.

21271218 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1772596 + ... + 1772607.

It is an arithmetic number, because the mean of its divisors is an integer number (5317806).

Almost surely, 2^21271218 is an apocalyptic number.

21271218 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21271218 is a wasteful number, since it uses less digits than its factorization.

21271218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3545208.

The product of its digits is 448, while the sum is 24.

The square root of 21271218 is about 4612.0730696727. The cubic root of 21271218 is about 277.0750707745.

The spelling of 21271218 in words is "twenty-one million, two hundred seventy-one thousand, two hundred eighteen".